Air-conditioning assembly for a rail vehicle

ABSTRACT

An air-conditioning assembly for a rail vehicle includes an air distribution box, which has an air inlet and at least two air outlets for connecting to outgoing air ducts. A throttling device is associated with each air outlet. The throttling device is arranged between the air outlet and an air division chamber inside the air distribution box. In the air division chamber the air flow coming from the air inlet is divided into at least two partial air flows. Pressure loss factors of the at least two throttling devices are chosen in such a way that a specified value results for a ratio of volumetric air flows at the at least two air outlets.

The invention relates to an air-conditioning arrangement for a rail vehicle, having an air distribution box which has an air inlet and at least two air outlets for connection to continuing air channels. Air distribution boxes and other components with air distribution properties, such as sound absorbers, are used in rail vehicles in order to supply different components of the air channel system with the required quantities of air. Air distribution boxes regularly form the interface to an air-conditioning device, in particular a compact air-conditioning device, which supplies air which is provided to the air distribution box via the air inlet.

However, the air distribution box cannot perform the air distribution function thereof for a wide variety of different rail vehicles and consequently also different air channel arrangements. Therefore, with known air channel arrangements, depending on the rail vehicle carriage configuration on the air distribution box, an adjustment is carried out by means of throttling at the air outlets. An adjustment which is carried out is then verified by means of tests, for example, in a climate chamber, until the appropriate adjustment for the present rail vehicle configuration is found. In this instance, non-linear properties of the typically complex air channel arrangement lead to a high number of test steps.

Based on this, an object of the invention is to develop an air-conditioning arrangement of the type mentioned in the introduction in such a manner that the establishment of the appropriate adjustment for the throttling at the air outlets of the air distribution box is reduced in terms of the complexity thereof.

This object is achieved with an air-conditioning arrangement mentioned in the introduction in that there is associated with each air outlet a throttle device which is arranged between the air outlet and an air division space within the air distribution box, in which the air flow originating from the air inlet is divided over at least two part-air flows, wherein pressure loss coefficients of the at least two throttle devices are selected in such a manner that a predetermined value is produced for a relationship of air volume flows at the at least two air outlets.

The use of the throttle devices which are associated with the respective air outlets enables a rough adjustment to be carried out for the relationship of the air volume flows at the air outlets so that, in one and the same air distribution box used in different rail vehicles with different air channel arrangements, only fine adjustments for throttles downstream of the air outlets are still required. This reduces the complexity with respect to the adjustment of the air channel arrangement in order to obtain desired air volume flows in the continuing air channels.

The pressure loss coefficients of the at least two throttle devices typically have a relationship with each other which corresponds to a quadratic relationship of air flow speeds in the region of the at least two air outlets. In this manner, the required pressure loss coefficients can be derived with reference to the flow speeds desired at the air outlets in each case.

The pressure loss coefficients of the at least two throttle devices can be selected in such a manner that a pressure loss which occurs in each case at the throttle devices corresponds to at least double the pressure loss of an air channel system which is connected to the air outlet. This pressure loss at the throttle devices may also correspond to a multiple of the pressure loss of the air channel system which is connected to the air outlet. This procedure has the advantage that the throttle devices reduce non-linear properties of the air volume flows and consequently also unpredictable effects for the fine adjustment of the air volume flows at the air outlets.

For example, the air pressure loss coefficients of the at least two throttle devices may in each case be greater than 7. This value ensures that the pressure loss at the respective throttle device is generally greater in rail vehicles than the pressure loss of continuing air channels.

The at least two throttle devices may preferably each be formed by a perforated plate. In this instance, the perforated plates may have a relationship of plate thickness to hole diameter of more than 1.5. This has the advantage that the perforated plates have the effect of a rectifier so that the action of non-linear properties of the air flows is further reduced. Unfavorable effects of occurrences of detachment on heating/cooling flaps with which air distribution boxes are regularly provided, are also effectively reduced by the rectifier function of the perforated plates.

A sound absorption device may be provided between the air inlet and the air division space. Such sound absorption devices are ideally configured in such a manner that occurrences of turbulence of the air flow are reduced. Preferably in this instance, the sound absorption device can be constructed in such a manner that an air flow originating from the air inlet is divided over a plurality of flow paths which are arranged beside each other and is combined again downstream of the sound absorption device. There is thereby produced an air distribution function of the sound absorption device which, as explained above, is advantageous for a subsequent fine adjustment of the air channel arrangement in the rail vehicle.

An embodiment of the invention is explained in greater detail below with reference to the drawings, in which:

FIG. 1 is a cross-sectional view of an air distribution box for connection to continuing air channels within a rail vehicle, and

FIG. 2 is a perspective view of the air distribution box of FIG. 1.

As illustrated in FIG. 1, an air distribution box 1 has an air inlet 2 which will typically be connected to an air-conditioning device of a rail vehicle. From the air inlet 2, air to be transported to the inner side of the rail vehicle first flows through a sound absorption device 3, which is formed in the embodiment illustrated by four flow paths 4 which are arranged beside each other and which are each located at a small angle with respect to each other. After leaving the sound absorption device 3, the incoming air reaches an air division space 4 within the air distribution box 1, in which space the air flow arriving from the air inlet 2 is divided over two part-air flows, as illustrated in FIG. 1 by arrows.

The air distribution box 1 is provided with two air outlets 5, 6 via which the respective part-air flows are transported to continuing air channels which are connected to the outlets 5, 6.

In this instance, a throttle device which is constructed as a perforated plate 7, 8 is associated with each of the air outlets 5, 6, wherein the respective perforated plate 7, 8 is arranged between the air outlet 5, 6 which is associated therewith and the air division space 4. Between the perforated plates 7, 8 and the associated air outlets 5, 6, the part-air flows are guided by channel elements 9, 10.

The perforated plates 7, 8 have pressure loss coefficients which are sized in such a manner that a predetermined value is produced for a relationship of air volume flows of the two part-air flows at the air outlets 5, 6. In this instance, the relationship of the pressure loss coefficients of the perforated plates 7, 8 corresponds to the quadratic relationship of the flow speeds in the region of the air outlets 5, 6.

The perforated plates 7, 8 have a relationship of plate thickness to hole diameter greater than 1.5 so that the perforated plates 7, 8 have additional properties of a rectifier. (Idelchick, Handbook of hydraulic resistance, Springer Verlag, 1986, Page 404, diagram 8-3).

For example, one of the perforated plates 7, 8 may be 30 mm thick, may have holes having a diameter of 20 mm and a free cross-section of approximately 35%. Such a perforated plate has a pressure loss coefficient of approximately 7.5. This value ensures that the pressure loss coefficient of the perforated plate 7, 8 corresponds to at least double the pressure loss of typical rail vehicle air channel systems which are connected to the air outlets 5, 6. In order to adjust the intended rough adjustment for the relationship of the air volume flows at the outlets 5, 6, the pressure loss coefficients of the perforated plates 7, 8 are intended to be selected accordingly. For example, the pressure loss coefficients of 7.5 and 12.0 bring about for the perforated plates 7, 8 in the air-conditioning arrangement shown an air volume flow relationship of 1:1.8. Other relationships can be produced by means of appropriate adjustment of the pressure loss coefficients of the perforated plates used.

The perforated plates 7, 8 are arranged substantially perpendicularly to the air flows which are present in the region thereof so that they bring about a desired pressure loss before the part-air flows leave the air distribution box at the air outlets 5 and 6.

The rough adjustment of the volume flow distribution brought about by the perforated plates 7, 8 for different configurations of rail vehicle carriages at the air distribution box 1 reduces the adjustment complexity on the individual carriages (end carriage, center carriage) since only a fine adjustment still has to be carried out. Effects of the fine adjustment are reduced by the rectifying action both of the sound absorption device 3 and the perforated plates 7, 8 by means of damping of the non-linear properties. A positive effect of the rough adjustment of the volume flow distribution, which adjustment is brought about by the perforated plates 7, 8, may involve previously required air guiding devices, such as metal guiding sheets and redirection members, being able to be dispensed with where applicable. 

1-8. (canceled)
 9. An air-conditioning arrangement for a rail vehicle, the air-conditioning arrangement comprising: an air distribution box formed with an air inlet and at least two air outlets for connection to continuing air channels; said air distribution box having an air division space within said air distribution box configured for dividing an air flow originating from said air inlet over at least two partial air flows; a throttle device associated with each of said air outlets and disposed between a respective said air outlet and said air division space; said at least two throttle devices having respective pressure loss coefficients selected to produce a predetermined value for a ratio of air volume flows at said at least two air outlets.
 10. The air-conditioning arrangement according to claim 9, wherein the pressure loss coefficients of said at least two throttle devices have a ratio between one another that corresponds to a quadratic relationship of air flow speeds at said at least two air outlets.
 11. The air-conditioning arrangement according to claim 9, wherein the pressure loss coefficients of said at least two throttle devices are selected such that a pressure loss in each of said throttle devices corresponds to at least twice a pressure loss in an air channel system connected to the respective said air outlet.
 12. The air-conditioning arrangement according to claim 9, wherein the pressure loss coefficients of said at least two throttle devices are in each case greater than respective pressure loss coefficients of a downstream channel system.
 13. The air-conditioning arrangement according to claim 9, wherein each of said at least two throttle devices is a perforated plate.
 14. The air-conditioning arrangement according to claim 13, wherein said perforated plate has a given plate thickness and perforations with a given hole diameter, and wherein a ratio between the plate thickness and the hole diameter is more than 1.5.
 15. The air-conditioning arrangement according to claim 9, which further comprises a sound absorption device disposed between said air inlet and said air division space.
 16. The air-conditioning arrangement according to claim 15, wherein said sound absorption device is configured to divide an air flow arriving from said air inlet over a plurality of flow paths arranged beside each other and recombined into a common air flow downstream of said sound absorption device in an air flow direction. 